1. Field of the Invention
The invention relates to apparatus for indicating the position of one body relative to another and to a variable inductance device for use in such apparatus.
2. Description of Related Art
A variety of inductive position sensing apparatus are known for sensing and indicating position. Typically these apparatus include a position sensing device including a coil with a particular winding configuration and a relatively movable member which is electromagnetically coupled to the coil. The inductance of the device varies with the relative position of the movable member and thus is an indication of the position.
The particular winding configuration chosen for a specific position sensing device of this type is an important factor in obtaining a desired inductance versus position relationship. Unfortunately, it is difficult to repeatably produce specific winding configurations in production quantities, and these are sometimes the most effective configurations for obtaining a particular desired relationship. Further, the dynamic environments in which the devices are frequently used may subject the windings to vibrational and shock forces which alter their configurations. Additionally, in uses which subject the devices to extreme temperature variations, such as in automotive applications, the winding configurations may be altered by thermal expansion and contraction. In either case, the alteration may be either temporary or permanent.